Packages with Thermal Management Features for Reduced Thermal Crosstalk and Methods of Forming Same

ABSTRACT

An embodiment package includes a first die stack on a surface of a package component, a second die stack on the surface of the package component, and a contour lid over the first die stack and second die stack. The contour lid includes a first thermal conductive portion over the first die stack, a second thermal conductive portion over the second die stack, and a thermal barrier portion between the first thermal conductive portion and the second thermal conductive portion. The thermal barrier portion includes a low thermal conductivity material.

BACKGROUND

In the packaging of integrated circuits, semiconductor dies may bestacked through bonding, and may be bonded to other package componentssuch as interposers and package substrates. The resulting packages areknown as Three-Dimensional Integrated Circuits (3DICs). Heat dissipationis a challenge in the 3DICs.

A bottleneck may exist in efficiently dissipating the heat generated inthe inner dies of the 3DICs. In a typical 3DIC, the heat generated ininner dies may have to be dissipated to outer components before the heatcan be conducted to a heat spreader. Between the stacked dies and outercomponents, however, there exist other materials such as underfill,molding compound, and the like, which are not effective in conductingheat. As a result, the heat may be trapped in an inner region of abottom stacked die and cause a sharp local temperature peak (sometimesreferred to as a hot spot). Furthermore, hot spots due to heat generatedby high-power consuming dies may cause thermal crosstalk problems forsurrounding dies, negatively affecting the surrounding dies' performanceand the reliability of the whole 3DIC package.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present invention, and theadvantages thereof, reference is now made to the following descriptionstaken in conjunction with the accompanying drawings, in which:

FIGS. 1A through 1J illustrate cross-sectional views of intermediatestages of manufacturing a 3DIC package in accordance with variousembodiments;

FIG. 2 illustrates a cross-sectional view of a 3DIC package inaccordance with alternative embodiments;

FIG. 3 illustrates a cross-sectional view of a 3DIC package inaccordance with alternative embodiments;

FIG. 4A through 4G illustrate a cross-sectional and top down views of a3DIC package in accordance with alternative embodiments;

FIGS. 5A and 5B illustrate cross-sectional and top down views of a 3DICpackage in accordance with alternative embodiments; and

FIGS. 6A through 6C illustrate a cross-sectional view, simulated contourplot, and simulated temperature plot of a 3DIC package and operationaltemperatures of the 3DIC package in accordance with various embodiments.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

The making and using of the embodiments of the disclosure are discussedin detail below. It should be appreciated, however, that the embodimentsprovide many applicable concepts that can be embodied in a wide varietyof specific contexts. The specific embodiments discussed areillustrative, and do not limit the scope of the disclosure.

Packages having thermal management features for reduced thermalcrosstalk and methods of forming same are provided in accordance withvarious exemplary embodiments. The intermediate stages of forming thepackages are illustrated. The variations of the embodiments arediscussed. Throughout the various views and illustrative embodiments,like reference numbers are used to designate like elements.

Embodiments will be described with respect to a specific context, namelychip-on-wafer-on-substrate (CoWoS) package. Other embodiments may alsobe applied, however, to other packages, including other threedimensional integrated circuits (3DIC) packages.

FIGS. 1A through 1H illustrate cross-sectional views of intermediatestages of manufacturing a 3DIC package, such as achip-on-wafer-on-substrate (CoWoS) package 100 in accordance withvarious embodiments. FIG. 1A illustrates a cross-sectional view of achip-on-wafer (CoW) package 50. CoW package 50 includes a high-powerconsuming die or die stack 10 disposed between two low-power consumingdie stacks 12 (sometimes referred to as chips 10 and 12). Die stack 10is high-power consuming die and may consume a relatively high amount ofpower, and hence generate a relatively large amount of heat, compared tolow-power consuming die stacks 12. For example, high-power consuming diestack 10 may consume between about 50 W and about 100 W of power whereaslow-power consuming die stacks 12 may consume between about 5 W andabout 10 W of power.

In some embodiments, die stack 10 may be a single system on chip (SoC)die, multiple SoC stacked dies, or the like. For example, FIG. 1Iillustrates a cross-sectional view of a CoWoS package 100 where diestack 10 includes multiple stacked dies (e.g., SoC dies) in accordancewith various embodiments. In some embodiments, die stacks 12 may be HBM(high bandwidth memory) and/or HMC (high memory cube) modules, which mayinclude memory dies 12 b bonded to a logic die 12 a. In alternativeembodiments, die stacks 10 and 12 may be other chips having otherfunctions. As illustrated by FIG. 1A, die stacks 10 and 12 may beencased in a molding compound 16. While FIG. 1A illustrates a CoWpackage 50 having one high-power die stack 10 and two low-power diestacks 12, other embodiments may include any number of high-power diestacks 10 and/or low-power die stacks 12.

Die stacks 10 and 12 are bonded to a top surface of a package component(e.g., interposer 18) through a plurality of connectors 14, which may bemicrobumps. In alternative embodiments, die stacks 10 and 12 may bebonded to a different package component such as a substrate, a printedcircuit board (PCB), or the like. Interposer 18 may be a wafer havinginterconnect structures for electrically connecting active devices (notshown) in die stacks 10 and 12 to form functional circuits. FIG. 1Billustrates a detailed cross-sectional view of interposer 18 inaccordance with various embodiments. A connector 14 of a die stack 10/12is electrically connected to a contact pad 22 on a top side ofinterposer 18. A passivation layer 24 may extend over a top surface ofinterposer 18 and cover edge portions of contact pad 22. Contact pad 22may be electrically connected to metallization layers 26. Metallizationlayers 26 may include metal lines 28 a and vias 28 b formed in adielectric material (e.g., a low-k dielectric material having a k valuelower than about 4.0 or even about 2.8). A through-substrate via (TSV)30 may electrically connect the metallization layer to a connector 20 ona backside of interposer 18.

In an embodiment, connectors 20 may be controlled collapse chipconnection (C4) bumps comprising solder. Connectors 20 may have a largercritical dimension (e.g., pitch) than connectors 14. For example,connectors 20 may have a pitch of about 100 μm while connectors 14 mayhave a pitch of about 40 μm. Interposer 18 may further have anunder-bump metallurgy (UBM) 32 connected to connector 20 and apassivation layer 34 on the backside of interposer 18. Otherconfigurations of interposer 18 may also be used.

Next CoW package 50 is bonded to a substrate 52 using connectors 20. Theresulting chip-on-wafer-on-substrate (CoWoS) package 100 is illustratedin FIG. 1C. Substrate 52 may be any suitable package substrate, such asa printed circuit board (PCB), an organic substrate, a ceramicsubstrate, a motherboard, or the like. Substrate 52 may be used tointerconnect CoW package 50 with other packages/devices (see for examplepackages/devices 11 in FIG. 1J) to form functional circuits. Asillustrated by FIG. 1J, these other packages and devices 11 may also bedisposed on a surface of substrate 52. Substrate 52 may further includecontacts 54 (e.g., ball grid array (BGA) balls) disposed on a surfaceopposite CoW package 50. Contacts 54 may be used to electrically connectthe CoWoS package 100 to a motherboard (not shown) or another devicecomponent of an electrical system.

In FIG. 1D, a reflow is performed to reflow and bond connectors 20 tosubstrate 52. Subsequently, an underfill 56 may be dispensed between CoWpackage 50 and substrate 52.

Next, referring to FIG. 1E, a thermal interface material (TIM) 58 isdispensed on CoW package 50. TIM 58 may be a polymer having a goodthermal conductivity (Tk), which may be between about 3 watts per meterkelvin (W/m·K) to about 5 W/m·K. In some embodiments, TIM 58 may includea polymer with thermal conductive fillers. The thermal conductivefillers may increase the effective Tk of TIM 58 to be between about 10W/m·K to about 50 W/m·K or more. Applicable thermal conductive fillermaterials may include aluminum oxide, boron nitride, aluminum nitride,aluminum, copper, silver, indium, a combination thereof, or the like. Inother embodiments, TIM 58 may comprise other materials such as ametallic-based or solder-based material comprising silver, indium paste,or the like. Although TIM 58 is illustrated as a continuous TIMextending over die stack 10 and die stacks 12, in other embodiments, TIM58 may be physically disconnected. For example, air gaps may be disposedin TIM 58 between adjacent dies (e.g., die stack 10 and/or die stacks12) to further reduce lateral thermal interaction between die stacks(e.g., as illustrated in FIG. 3).

An adhesive 60 (e.g., an epoxy, silicon resin, or the like) is dispensedover an otherwise unoccupied portion of substrate 52. Adhesive 60 mayhave a better adhering ability and a lower thermal conductivity than TIM58. For example, adhesive 60 may have a thermal conductivity lower thanabout 0.5 W/m·K. Adhesive 60 may be positioned so as to allow a heatdissipating feature (e.g., a contour ring 62, see FIG. 1F) to beattached around CoW package 50. Thus, in some embodiments, adhesive 60may be disposed around the perimeter of, or even encircle, CoW package50.

FIG. 1F illustrates a sliced cross-sectional view of CoWoS package 100after the attachment of a heat dissipating contour ring 62 to substrate52. In a top-down view of CoWoS package 100 (not shown), contour ring 62may encircle CoW package 50. A bottom surface of contour ring 62 may beadhered to substrate 52 using adhesive 60. Contour ring 62 may have ahigh thermal conductivity, for example, between about 200 W/m·K to about400 W/m·K or more, and may be formed using a metal, a metal alloy, orthe like. For example, contour ring 62 may comprise metals and/or metalalloys such as Al, Cu, Ni, Co, combinations thereof, and the like.Contour ring 62 may also be formed of a composite material, for examplesilicon carbide, aluminum nitride, graphite, and the like. An adhesive64, which may be substantially similar to adhesive 60, may be dispensedover a top surface of contour ring 62.

Next, referring to FIG. 1G, a heat dissipating contour lid 66 is mountedover CoW package 50 and contour ring 62. Contour lid 66 may be adheredto contour ring 62 through adhesive 64. Contour lid 66 may be formed ofsubstantially similar materials as contour ring 62, which have a highthermal conductivity, for example, between about 200 W/m·K to about 400W/m·K or more.

Bottom surfaces of contour lid 66 may be in physical contact with TIM58. These bottom surfaces in contact with TIM 58 may be aligned withlow-power consuming die stacks 124-0, and heat may be conducted awayfrom low-power consuming die stacks 12 through TIM 58 and contour lid66. Contour lid 66 may further include an opening 70, which may bealigned with high-power consuming die stack 10. In the embodimentillustrated in FIG. 1G, because the material of lid 66 is excluded fromopening 70, heat generated by the high power die stack 10 may not besignificantly dissipated and spread through lid 66. As a result, thermalcrosstalk between die stacks 10 and 12 may be reduced. The high heatgenerated in the die stack 10 may be conducted away by a heat spreader72 (see FIG. 1H) as will be explained in later sections.

TIM 68, which may be substantially similar to TIM 58, may be dispensedover top surfaces of contour lid 66. Generally, the combination ofcontour ring 62 and contour lid 66 may be referred to as heatdissipation feature 62/66. While FIG. 1G illustrates contour ring 62 andcontour lid 66 as separate pieces, in alternative embodiments, contourring 62 and contour lid 66 may be a single piece heat dissipationfeature 62/66 (e.g., see FIG. 5).

FIG. 1H illustrates the attachment of a composite heat spreader 72 overcontour lid 66 and TIM 68 in CoWoS package 100. Heat spreader 72 may beattached onto the CoWoS package 100 with a mechanical fastener connectedto a mother board of the system (not shown). Other mechanisms forattaching heat spreader 72 may also be used. In various embodiments,composite heat spreader 72 may be a heat sink or a portion of a heatsink, which may include a cooling element 76 (e.g., a fan). Compositeheat spreader 72 may extend laterally past outer sidewalls of contourring 62/contour lid 66, allowing for increased heat dissipation over awider surface area.

Composite heat spreader 72 may include thermal conductive portions 72 aand 72 b formed of high Tk materials, which may be substantially similarto the materials of heat dissipation feature 62/66. Thermal conductiveportions 72 a and 72 b may be aligned over high-power die stack 10 andlow-power die stacks 12, respectively. Furthermore, thermal conductiveportion 72 a over die stack 10 may extend into opening 70 of contour lid66. A bottom surface of thermal conductive portion 72 a may be inphysical contact with TIM 58 and may conduct heat away from die stack 10as indicated by arrows 74. Thermal conductive portions 72 b may be inphysical contact with TIM 68 disposed over die stacks 12. Thus, as alsoindicated by arrows 74, composite heat spreader 72 helps conduct heataway from low-power die stacks 12 through thermal conductive portions 72b, TIM 68, contour lid 66, and TIM 58.

Composite heat spreader 72 may further include thermal barrier portions72 c disposed between thermal conductive portions 72 a and 72 b. Thermalbarrier portions 72 c may comprise a low Tk material, for example,having a thermal conductivity less than about 0.5 W/m·K. In someembodiments, thermal barrier portions 72 c comprise epoxy, unsaturatedpolyesters, phenolics, adhesives, air gaps (e.g., trenches orthrough-holes, discussed in greater detail below), combinations thereof,or the like. Thermal barrier portions 72 c may have a horizontaldimension W1, which may be greater than about 0.5 mm, 1 mm, or even 5 mmdepending on layout design. Thermal barrier portions 72 c reduces thelateral spreading of heat conducted from die stacks 10 and 12 throughcontour lid 66, TIMs 58 and 68, and composite heat spreader 72. Thermalbarrier portions 72 c provide separate zones for thermal management foreach die stack 10 and 12, reducing thermal crosstalk. Thus, by includingthe various thermal management features of CoWoS package 100 (e.g.,composite heat spreader 72 and contour lid 66), heat may be dissipatedin a generally vertical, as opposed to lateral, direction away from diestacks 10 and 12 as indicated by arrows 74. Thermal crosstalk may bereduced and device performance may be improved.

FIG. 2 illustrates a cross-sectional view of CoWoS package 200 inaccordance with alternative embodiments. CoWoS package 200 may besubstantially similar to CoWoS package 100, where like referencenumerals correspond with like elements. However, the configuration ofcontour lid 66 and heat spreader 72 may be different in CoWoS package200. In CoWoS package 200, contour lid 66 may include two openings 70disposed over low-power die stacks 12. TIM 58 may be dispensed over atop surface of high-power die stack 10, and a bottom surface of contourlid 66 may be in physical contact with portions of TIM 58 overhigh-power die stack 10.

Furthermore, heat spreader 72 may include thermal conductive portions 72b over die stacks 12, which extend into openings 70. A bottom surface ofthermal conductive portion 72 b may be in physical contact with portionsof TIM 58 over low-power die stacks 12, and thermal conductive portions72 b may thus conduct heat away from die stacks 12. Thermal conductiveportions 72 a may be in physical contact with TIM 68 disposed overhigh-power die stack 10. Thus, composite heat spreader 72 helps conductheat away from die stack 10 through thermal conductive portions 72 a,TIM 68, contour lid 66, and TIM 58. Heat spreader 72 further includesthermal barrier portions 72 c (e.g. comprising a low Tk material)disposed between thermal conductive portions 72 a and 72 b. Thus, heatspreader 72 reduces the lateral dissipation of heat and thermalcrosstalk in CoWoS package 200.

FIG. 3 illustrates cross-sectional view of a CoWoS package 300 inaccordance with various alternative embodiments. Package 300 issubstantially similar to package 100, wherein like reference numberscorrespond to like elements. However, the configurations of heatspreader 72 and contour lid 66 may be altered. Notably, package 300includes a composite contour lid 66, which may not include openings(e.g., openings 70 in CoWoS package 100) aligned with die stack 10 ordie stack 12. Instead, contour lid 66 may include thermal conductiveportions 66 a disposed over each die stack 10 and 12. Thermal barrierportions 66 b may be disposed between thermal conductive portions 66 a.Thermal conductive portions 66 a may be formed of substantially similarmaterials as thermal conductive portions 72 a/72 b and thermal barrierportions 66 b as thermal barrier portions 72 c, respectively. Bottomsurfaces of thermal conductive portions 66 a maybe in physical contactwith TIM 58. In some embodiments (such as the one illustrated in FIG.3), TIM 58 may be separated into physically disconnected TIM portions 58a through 58 c. Each TIM 58 a through 58 c may be disposed over aseparate die stack 10 or 12. Thermal barrier portions 66 b of compositecontour lid 66 reduces lateral diffusion of heat during thermaldissipation.

Furthermore, CoWoS package 300 may include TIM 68 disposed over contourlid 66 and a composite heat spreader 72 over and contacting TIM 68. Heatspreader 72 includes thermal conductive portions 72 a/72 b over each diestack 10/12 and thermal barrier portions 72 c between thermal conductiveportions 72 a/72 b. Heat spreader 72 further reduces the lateraldiffusion of heat during operations to reduce thermal crosstalk andimprove device performance.

FIG. 4A illustrates a cross-sectional view of a CoWoS package 400 inaccordance with various alternative embodiments. Package 400 issubstantially similar to package 300, wherein like reference numberscorrespond to like elements. Composite contour lid 66 may includethermal conductive portions 66 a disposed over die stacks 10 and 12.Composite contour lid 66 may further include thermal barrier portions 66c disposed between thermal conductive portions 66 a. Thermal barrierportions 66 c in CoWoS package 400 may be air gaps and may not includeany materials disposed therein. Because air has a thermal conductivityless than about 0.02 W/m·K, the inclusion of such air gaps as thermalbarrier portions 66 c may reduce the lateral dissipation of heat andthermal crosstalk in CoWoS package 400. Package 400 may further includeTIM 68 (not shown) and a composite heat spreader 72 (not shown) disposedover contour lid 66.

FIGS. 4B through 4D illustrate top-down views of alternativeconfigurations of composite contour lids 66 having air gaps as thermalbarrier portions 66 c. Composite contour lid 66 may be disposed overhigh-power die stacks 10 and/or low-power die stacks 12, which are shownin ghost in FIGS. 4B through 4D. Thermal conductive portions 66 a may bedisposed over such die stacks 10/12 for conducting heat away from diestacks 10/12. Thermal barrier portions 66 c may be disposed in regionsbetween die stacks 10/12 (referred to as thermal crosstalk regions) toreduce the lateral dissipation of heat and thermal crosstalk. Thermalbarrier portions 66 c may include air gaps that are configured astrenches (e.g., illustrated in FIG. 4B), one or more through-holes(e.g., illustrated in FIG. 4C), or a combination thereof (e.g.,illustrated in FIG. 4D).

In various alternative embodiments, composite contour lid 66 may includeboth thermal barrier portions 66 b (e.g., comprising a low Tk material)and thermal barrier portions 66 c (e.g., air gaps). FIGS. 4E through 4Gillustrate top-down views of alternative configurations of compositecontour lid 66 having both thermal barrier portions 66 b and thermalbarrier portions 66 c. Thermal barrier portions 66 b may comprise low Tkmaterials and may be configured in combination with trenches (e.g.,illustrated in FIG. 4E), through-holes (e.g., illustrated in FIG. 4F),or a combination of trenches and through-holes (e.g., illustrated inFIG. 4G). Thermal barrier portions 66 b and 66 c may be disposed betweendie stacks 10/12 to reduce lateral dissipation of heat and thermalcrosstalk. Although FIGS. 4B through 4G illustrate composite contour lid66, similar configurations may also be applied to composite heatspreader 72 having thermal barrier portions 72 c. That is, thermalbarrier portions 72 c of composite heat spreader 72 may also compriselow Tk materials, air gap trenches, air gap through-holes, or acombination thereof.

FIG. 5A illustrates a sliced cross-sectional view of a package 500 inaccordance with various alternative embodiments having multiplehigh-power die stacks 10 and/or low-power die stacks 12 having differentheights. Package 500 is substantially similar to package 100, whereinlike reference numbers correspond to like elements. However, package 500may include a high-power die stack 10 having a height H2 and a low-powerdie stack 12 having a height H1. Die stack 12 may be encased in amolding compound 16, which may or may not incase die stack 10. Height H1may be different than height H2. Although FIG. 5 illustrates height H1as greater than height H2, in alternative embodiments, height H1 may beless than height H2. Furthermore, the die stacks in package 500 may behigh-power die stacks 10, low-power die stacks 12, or a combinationthereof.

Die stacks 10 and 12 may be electrically connected to an interposer 18.Passive devices 78 (e.g., capacitors, resistors, inductors, varactors,and/or the like) may also be electrically connected to interposer 18.Alternatively, die stacks 10 and 12 and passive devices 78 may beattached to an organic or ceramic substrate. TIM 58 a and 58 b may bedisposed over and contacting a top surface of die stacks 10 and 12,respectively. A thermal conductive feature 62/66 (e.g., a single-piececontour ring and lid) may be adhered to the substrate through adhesive60. Thermal conductive feature 62/66 may cover die stack 12. A bottomsurface of thermal conductive feature 62/66 may be in physical contactwith TIM 58 b. Furthermore, thermal conductive feature 62/66 may have anopening 70 aligned with die stack 10. TIM 68 may be disposed over and inphysical contact with a portion of thermal conductive feature 62/66 thatis in contact with TIM 58 b. Adhesive 60′ (which may be substantiallysimilar to adhesive 60) may be disposed over other portions of thermalconductive features 62/66, for example, portions that are substantiallyfree of underlying thermal contacts. FIG. 5B illustrates a top-down viewof thermal conductive features 62/66 having opening 70. As illustratedin FIG. 5B, TIM 68 and adhesive 60's may be disposed over differentportions of thermal conductive features 62/66.

Referring back to FIG. 5A, a composite heat spreader 72 is disposed overTIM 68 and adhesive 60 a thermal conductive feature 62/66. Compositeheat spreader 72 includes thermal conductive portions 72 a and 72 b.Thermal conductive portions 72 b may be disposed over die stack 12 andmay be in physical contact with TIM 68. Thermal conductive portion 72 amay extend into opening 70 and be in physical contact with TIM 58 a overdie stack 10. A thermal barrier portion 72 c (e.g., comprising a low Tkmaterial) may be disposed between thermal conductive portions 72 a and72 b. Thus a package having die stacks of different heights may includethermal management features which reduce the lateral dissipation of heatthrough thermal conductive feature 62/66 and composite heat spreader 72.

By using thermal management features (e.g., a combination of a contourlid and composite heat spreader), the lateral heat dissipation andthermal crosstalk may be reduced. For example, FIG. 6A illustrates apackage 600 having a high-power die stack 10 and a low-power die stack12 having such heat management features (e.g., contour lid 66 andcomposite heat spreader 72). Package 600 may be substantially similar topackage 100 where like reference numerals represent like elements. Acontour plot 602 from a simulation to simulate the temperaturedistribution in the package 600 during the operation of die stacks 10and 12 is illustrated in FIG. 6B. As shown in FIG. 6B, heat flow fromhigh-power die stack 10 was generally limited to a substantiallyvertical direction with reduced lateral heat dissipation. Furthermore,operation temperatures of package 600 were reduced from operationaltemperatures of conventional packages. For example, in the simulations,operational temperatures of package 600 ranged from about 50.9° C. toabout 75.5° C., whereas operational temperatures of conventionalpackages range from about 90.1° C. to about 51.9° C.

FIG. 6C illustrates a temperature plot 604 of operational temperaturesacross a conventional package (e.g., as represented by line 606) andpackage 600 (e.g., as represented by line 608) in the simulation. Region610 corresponds to a thermal crosstalk region in the packages betweendie stacks 10 and 12. As illustrated by plot 604, by adopting thethermal management features illustrated in FIG. 6A, the temperature ofthe package in thermal crosstalk region 610 was reduced. Therefore, byadopting the thermal management features of the embodiments of thepresent disclosure, not only the operation temperatures of the packagesare reduced, but also the temperature of regions between die stacks isreduced. As a result, thermal crosstalk and lateral dissipation of heatare reduced.

In accordance with an embodiment, a package includes a first die stackon a surface of a package component, a second die stack on the surfaceof the package component, and a heat-dissipating contour lid coveringthe first die stack. The heat dissipating contour lid includes anopening over the second die stack.

In accordance with another embodiment, a package includes a first diestack on a surface of a package component, a second die stack on thesurface of the package component, and a contour lid over the first diestack and second die stack. The contour lid includes a first thermalconductive portion over the first die stack, a second thermal conductiveportion over the second die stack, and a thermal barrier portion betweenthe first thermal conductive portion and the second thermal conductiveportion. The thermal barrier portion comprises a low thermalconductivity material

In accordance with yet another embodiment, a method includeselectrically connecting a first die stack and a second die stack to asubstrate and dispensing a thermal interface material (TIM) on a topsurface of the first die stack. The method further includes forming acontour lid over the first die stack. The contour lid includes a thermalconductive portion physically contacting the TIM and a thermal barrieradjacent to the thermal conductive portion.

Although the embodiments and their advantages have been described indetail, it should be understood that various changes, substitutions andalterations can be made herein without departing from the spirit andscope of the embodiments as defined by the appended claims. Moreover,the scope of the present application is not intended to be limited tothe particular embodiments of the process, machine, manufacture, andcomposition of matter, means, methods and steps described in thespecification. As one of ordinary skill in the art will readilyappreciate from the disclosure, processes, machines, manufacture,compositions of matter, means, methods, or steps, presently existing orlater to be developed, that perform substantially the same function orachieve substantially the same result as the corresponding embodimentsdescribed herein may be utilized according to the disclosure.Accordingly, the appended claims are intended to include within theirscope such processes, machines, manufacture, compositions of matter,means, methods, or steps. In addition, each claim constitutes a separateembodiment, and the combination of various claims and embodiments arewithin the scope of the disclosure.

What is claimed is:
 1. A package comprising: a first die stack on asurface of a package component; a second die stack on the surface of thepackage component; and a heat-dissipating contour lid covering the firstdie stack, wherein the heat-dissipating contour lid comprises an openingover the second die stack.
 2. The package of claim 1, furthercomprising, a first thermal interface material (TIM) disposed on a topsurface of the first die stack, wherein the heat dissipating contour lidis in physical contact with the first TIM.
 3. The package of claim 1,further comprising: a second thermal interface material (TIM) disposedon a top surface of the second die stack; and a composite heat spreaderover the heat-dissipating contour lid, wherein the composite heatspreader comprises a first thermal conductive portion over the firstdie, a second thermal conductive portion extending into the opening andcontacting the second TIM, and a thermal barrier portion disposedbetween the first thermal conductive portion and the second thermalconductive portion.
 4. The package of claim 3, further comprising athird TIM disposed on a top surface of the heat-dissipating contour lid,wherein the first thermal conductive portion is in physical contact withthe third TIM.
 5. The package of claim 3, wherein thermal barrierportion comprises a low thermal conductivity material having a thermalconductivity less than about 0.05 watts per meter kelvin, one or moreair gaps, or a combination thereof.
 6. The package of claim 3, whereinthe composite heat spreader further comprises a cooling element.
 7. Thepackage of claim 1, further comprising a heat dissipating contour ringsurrounding the first die stack and the second die stack, wherein theheat dissipating contour lid is over and attached to the heatdissipating contour ring.
 8. The package of claim 1, wherein the heatdissipating contour lid comprises aluminum, copper, nickel, cobalt, or acombination thereof.
 9. The package of claim 1, wherein the first diestack has a first height, and wherein the second die stack has a secondheight different than the first height.
 10. A package comprising: afirst die stack on a surface of a package component; a second die stackon the surface of the package component; and a contour lid over thefirst die stack and second die stack, wherein the contour lid comprises:a first thermal conductive portion over the first die stack; a secondthermal conductive portion over the second die stack; and a firstthermal barrier portion between the first thermal conductive portion andthe second thermal conductive portion, wherein the first thermal barrierportion comprises a low thermal conductivity material.
 11. The packageof claim 10, further comprising a first thermal interface material (TIM)on a top surface of the first die stack and a second TIM on a topsurface of the second die stack, wherein the first thermal conductiveportion is in physical contact with the first TIM, and wherein thesecond thermal conductive portion is in physical contact with the secondTIM.
 12. The package of claim 11, wherein the first TIM is physicallydisconnected from the second TIM.
 13. The package of claim 10, whereinthe first thermal barrier portion comprises an epoxy, an unsaturatedpolyester, a phenolic, an adhesive, or a combination thereof.
 14. Thepackage of claim 10, wherein the first thermal barrier portion comprisesone or more through holes.
 15. The package of claim 10, wherein thefirst thermal barrier portion comprises a trench.
 16. The package ofclaim 10, wherein the first thermal barrier portion comprises acombination of an air gap and a low thermal conductivity material. 17.The package of claim 10, further comprising a composite heat spreaderover the contour lid, wherein the composite heat spreader comprises: athird thermal conductive portion over the first thermal conductiveportion; a fourth thermal conductive portion over the second thermalconductive portion; and a second thermal barrier portion between thethird thermal conductive portion and the fourth thermal conductiveportion, wherein the second thermal barrier portion comprises a lowthermal conductivity material.
 18. A method comprising: electricallyconnecting a first die stack to a substrate; electrically connecting asecond die stack to the substrate; dispensing a first thermal interfacematerial (TIM) on a top surface of the first die stack; forming acontour lid over the first die stack, wherein the contour lid comprises:a first thermal conductive portion physically contacting the first TIM;and a first thermal barrier adjacent to the first thermal conductiveportion.
 19. The method of claim 18, wherein the first thermal barrieris an opening in the contour lid over the second die stack, the methodfurther comprising forming a composite heat spreader over the contourlid, wherein the composite heat spreader comprises a second thermalconductive portion over the first die stack, a third thermal conductiveportion extending in the opening, and a second thermal barrier betweenthe second and third thermal conductive portions.
 20. The method ofclaim 18, wherein the contour lid further comprises a fourth thermalconductive portion physically contacting a second TIM on a stop surfaceof the second die stack, wherein the first thermal barrier is disposedbetween the first and fourth thermal conductive portions.